mudbilly

HI All,

I'm getting ready to upgrade the front brakes on my 2006 LT from factory stock to the larger SS version with the Brembo calipers.

My mechanic wants to know if the brake master cylinder is the same for these ?

I called the local GM dealer and was told that they would have no way of confirming this unless I gave them the Vin # for both vehicles.

I know people here have done this swap, but didn't see anything about the master cylinder in any of the threads.

We are going to do a dry run next week to make sure that everything will fit with my aftermarket wheels. If not, I will need get new wheels before I buy the new tires that I need before winter :) I don't want to go the spacer route.

thanks

firemangeorge

Since you're modifying the brake system, the GM dealer can't give you any kind of answer.
Pretty sure all the folks who have done this swap are using their stock master cylinder. Since it's only a swap to bigger brakes up front and you will still have drums in the rear, the master cylinder should perform the same function.

Now, the SS with it's 4 wheel discs may have a different MC. Not exactly sure. But, the SS does have a different brake modulator valve than the regular HHR's.

What size are your aftermarket wheels? Some 17's may clear. 18's shouldn't be a problem. 19's or 20's will have plenty of room.

donbrew

You could go shopping for parts online and compare part numbers.

mudbilly

uh, i only have 16" wheels, so i guess i am in for new rims..... that is why i wanted to have this done as a dry run first, it gives me time to get the rims before i buy new tires,

i need fat tires because i do alot of camping, with canoes and bikes on the roof and the back filled with gear, also the roads around the swamp are full of pot holes and big rims with skinny tires means lots of damaged rims

so, i'd probaby try to find 17 inchers that can clear the brakes

any idea why the valve is different, or if it needs to be swapped ? what does it do ? i've heard of proportioning valves, but i'm pretty old school.

i can't really find anything about the master cylinder online, i guess that nobody ever needs to buy one. the cap is the same, for whatever that is worth

firemangeorge

I would guess the valve is different because of the 4 wheel disc vs 2 wheel disc setup.
No, you won't need to change the valve. I just stated there was a difference to show the SS has some different parts.

donbrew

People change master cylinders every day. They are in every parts catalog.

mudbilly

you're right, at first I just called pep boys down the street and they said they didn't sell them, but I guess that is just something they don't handle,

looking online at autoparts warehouse, it lists different master cylinders, but I don't know if that affects the braking, or if it is just something for fit or just because it is a different year, the SS was not offered in 2006.

in the 2008 models there are 3 versions that have the same part # listed for both the LT and SS models., but the LT model also has a couple other versions not listed for the SS ..

firemangeorge

The master cylinders may be the same but if it comes with the reservoir then you could have two different part numbers.
Auto trans HHR's have a different reservoir than the 5 speeds.
On the 5 speed, the reservoir holds the fluid for the brakes AND the clutch hydro system.

mudbilly

cool, I am going to treat this as a non-issue.

I do have the 5 speed though

the car goes to the shop Tuesday, i'll keep y'all updated.

mudbilly

well,

the 16's didn't stand a chance...... so I ordered a new set of 18's with tires from tire rack....... I spent ALOT of time trying to make sure that what I bought will fit, but I am still nervous.

they should be at the shop tomorrow/Friday and hopefully I'll have the new shoes on for kayaking/camping this weekend....

if there is any issues with brake feel because of the master cylinder, we are hoping that it will be relatively easy swapping that out with a SS version.

I don't have ABS, so hopefully there will not be any issues with the proportioning valve........